The subject matter herein relates to silicon photonics. More particularly, the subject matter relates to redundancy in optical paths of silicon photonics.
As computer technology advances, the need for faster data transfer has increased. Integrated circuit (IC chip) manufacturers have turned to silicon photonics to satisfy this need. The use of silicon photonics allows the transfer of data in the form of optical pulses. These pulses travel within an individual chip, and between chips, via silicon waveguides. However, before the data carried as optical signals can be reconverted into electrical form, the light must be detected. Accordingly, semiconductor detectors have been integrated into the waveguides to detect the optical pulses.
Conventionally, these integrated circuits are single waveguide systems. Therefore, a single optical detector is placed at the end of the waveguide to detect the optical signal. Optical detectors may include, but are not limited to, germanium detectors, graphene detectors, and silicon detectors. Each type of detector has its own yield problems. Germanium detectors, for example, can have a single detector yield as low as 70%. That is, a germanium detector may have a 30% probability of malfunctioning. Since conventional integrated circuits are single detector systems, a malfunctioning detector will prevent the whole integrated circuit system from functioning properly.
A malfunction within a detector may occur in a variety of ways. For example, a detector may have a short in its system. A functional detector may have a silicon waveguide, a detector, and metal contacts. A malfunctioning detector may have a bridge between the metal contacts resulting in a short in the system. Such an occurrence can exhibit very high dark current between the metal contacts and therefore cause damage to the circuit. A detector may also fail due to opens in the system or due to faulty manufacturing.